The inventive concepts described herein relate to a dual aperture camera with improved color gamut and an operating method thereof, and more particularly, relate to a dual aperture camera capable of improving color gamut by means of a dual band filter for selectively receiving two light signals having different wavelength ranges and an operating method thereof.
Referring to FIG. 1 which shows an operation of an infrared (IR) cut-off filter in a conventional dual aperture camera, an 810-nm cut-off filter is used as an IR cut-off filter 110 of the conventional dual aperture camera, and a CMOS image sensor (CIS) receives a light signal that has a wavelength range shorter than 810 nm.
A red (R) cell included in the CIS of the conventional dual aperture camera further receives an IR signal of a wavelength range 130 between 650 nm and 810 nm as much as 30% with respect to the whole light signal incident onto the R cell, other than a red signal of a wavelength range 120 between 580 nm and 650 nm. For this reason, both the IR signal and the R signal are processed when the R cell, included in the CIS of the conventional dual aperture camera, processes light signals to generate images, thereby causing the problem with color gamut. For example, a feeling of color of an image about a green plant or nylon-based clothes partially turns red.
Crosstalk of RGB cells may influence an image that is generated upon the RGB cells processing RGB signals. Thus, an error occurs at a depth extracting operation because the image having the problem with the color gamut is used. In particular, the R cell is influenced as much as about 18% even considering a decrease in the amount of light due to the pin hole. For this reason, an error may occur upon extracting of the depth about the R signal because an image formed of the R signal becomes clear, not sufficiently blur. For example, when the R cell is further influenced as much as about 18%, an 8-level depth error may occur at a depth level of 47.
Also, the conventional dual aperture camera further contains an infrared emitting diode (IRED) that generates a light signal of a 780-nm wavelength range allowing taking a picture indoors or at a dim environment. The light signal of the 780-nm wavelength range generated from the IRED of the conventional dual aperture camera is problematic in that the light signal is perceived by a person. In addition, most IREDs generate a light signal of a 850-nm or 940-nm wavelength range. In this regard, the light signal of the 780-nm wavelength range which the IRED of the conventional dual aperture camera generates is unmarketable.
Thus, it is provided a technique for making the color gamut of a dual aperture camera better by means of a dual band filter for selectively receiving two light signals of which the wavelength ranges are different from each other.